Re: Introspecting yas tab binding

[Psionic K <psionik@positron.solutions>]

It's solved.  The general method is described at the end.

> For the first question, we have trace.el, stepping through Lisp code
> in Edebug, and stepping through code in keyboard.c in GDB.  For the
> second, I would modify the offending menu entry in some way that would
> signal that it is responsible

I re-bound the command to "X" like so:

    (setcar  (car(last yas-minor-mode-map)) (string-to-char "X"))

This confirmed the responsibility of the menu binding, the contents of
which are:

    (9 menu-item "" yas-expand :filter yas-maybe-expand-abbrev-key-filter)

> The fact that :filter function cannot be debugged using debug-on-entry
> perhaps warrants a bug report.

I confirmed that `trace-function' was able to see the filter be
called.  However, debug-on-entry did not trigger a debugger session.

`key-binding' succeeds in uncovering that a binding exists, but not where it is.

Identifying keymaps from `current-active-maps' and corroborating the
symbol names with the obarray values, then calling `keymap-lookup'
appears to be viable.

The `keymap-lookup' returns nil or `yas-expand' depending on the
:filter result.  The user must configure the filter to be true to
observer the binding.  This is the only such conditional binding I
have observed in Emacs that didn't rely on variables in
`emulation-mode-alists` or modifying keymaps themselves.